Point of Intersection
by RogueJacksonators
Summary: "We're asymptotic to each other, torturously close, but never ever going to meet." / In which Stiles and Allison are siblings, and Scott and Lydia have been best friends since childhood.
Stiles and Allison first go to school together during his sophomore year in high school. They were in different schools when Allison became part of his family and his father had seen no reason to make either of them transfer schools then. Allison's old school followed a different system, which somehow landed her in Stiles' grade now she's finally attending public high school.

"Hey, do you have a spare pen?" Allison asks as they walk into English. They had been in different classes for first period. "I left my pencil case at home."

"Seriously? You had History with Howard! How did you get away with not taking notes?"

"Someone lent me a pen," Allison answers, and her cheeks turn a faint shade of pink. Stiles swings his bag over his shoulder and onto his chosen desk and squints at his sister. "Someone? Or some guy?"

Allison blushes harder. "He just lent me a pen!" she exclaims.

Stiles opens his mouth to press for the identity of this _he_ when he hears the signature _click clack_ of heels preceding _her_ presence. He turns to the door just as a petite girl with bright green eyes and beautiful strawberry blonde hair enters the classroom, making a beeline for the center seat in the second row - her seat of choice in every class - which happened to be the one in front of him. Not that that had anything to do with him choosing his desk.

Stiles raises his hand as she approaches the desk, a "Hey Lydia" forming on his lips. But then just as he finds his guts, she pauses and rummages through her handbag, missing his wave entirely. Stiles slumps back, watching as the girl pulls her phone out and takes her seat, her fiery hair swinging behind her. He doesn't know how hard her heart is pounding in her throat, or see the cold sweat across her forehead from when she saw that he was going to talk to her, or her phone in her lap as she types a "HE'S SITTING BEHIND ME" to her best friend.

To his right, Allison chuckles.

* * *

"So, I spoke to the famous Lydia Martin."

Stiles bangs his head against his locker door as he whips around to face his sister. He shuts the offending door to reveal a smug grin. "You _what?_ " Then he calms himself down. "Hey Stiles, how was your day?" he mutters under his breath.

Allison rolls her eyes. "She was with the guy - Scott - when I returned him his pen and introduced herself," she says casually. "And she invited me to watch you practice tomorrow."

"You mean she invited you to watch _Scott McCall_ practice," Stiles deadpans. "So he's the guy. No wonder he was looking at you during Econs." He has nothing against McCall - the guy would make a good lacrosse player if not for his asthma - he just envies how close he is to Lydia Martin. That, and the fact that he seems to be unknowingly leading Allison on despite already having the most beautiful girl alive.

* * *

Lacrosse is, well, lacrosse. Coach screeches at Greenberg and berates everyone else with new insults he came up with over the summer. Jackson Whittemore is a show-off. Ramirez is in goal.

Stiles spots Allison in the bleachers, next to Lydia - who now has a beanie hiding her strawberry blonde locks but still looking impossibly cute in her jacket and floral skirt, even from a distance. A textbook sits in her laps and he think of course she is studying while watching lacrosse practice. She is, after all, also the smartest person in school. Both girls seem to be looking in his general direction and his heart speeds up at the thought of Lydia Martin watching him. Then he shifts his gaze for a moment as Coach yells something incoherent and notices the '11 MCCALL' on the jersey in front of him. He sighs. Of course.

The first practice of the year usually ends early for existing members as the new freshman go through a fitness test. Tired and sore, Stiles drags himself out of the changing room where Allison is waiting for him in the hallway with her new friend.

"Als!" Stiles calls as he walks towards the two girls. They both turn around, Allison smiling at him and Lydia staring at him with wide eyes. He takes a deep breath as he steps up next to Allison. "Hi Lydia," he breaths, mentally cringing at how weird his voice sounds. He deals with it by running a hand through his newly grown-out hair. Lydia swallows and takes a small step back. Great, now she doesn't want to be near him.

His smiles falls off his face and he leaves with Allison before he makes a fool out of himself, unaware of the short girl watching his back as he leaves.

* * *

"We're asymptotic to each other, torturously close, but never ever going to meet," Stiles laments as they drive home.

Allison gives him an odd look from the passenger seat.

"Asymptote, you know, function sketching? When a graph approaches a line but never meets it."

The brunette frowns and shakes her head.

"Oh god, two days in school and you already need help in math." He gets backhanded lightly as they pull up in the Stilinski driveway.

"You know, you could try having a full conversation with Lydia," Allison suggests. "She's nice and easy to talk to. And then maybe she'll find out you're a nice guy."

He busies himself with getting his bag from the backseat and doesn't look up. "I guess, but I think she likes someone else." _Someone you like too. No wonder you two get along. You both have the hots for Scott McCall_.

Allison reaches over the console and pats his shoulder. "You're a smart guy, Stiles, but you can be really clueless sometimes."

* * *

He gets his first full conversation with Lydia Martin on Thursday night. It starts during lunch, when Allison comes up behind him, swinging her arm so it hits his shoulder as she passes. He rolls his eyes and she laughs at him and they do the half-hug thing they've been doing since they became siblings in middle school.

Scott and Lydia are a short distance behind Allison, conversing in low voices. Stiles briefly wonders what they're saying ("Because she's beautiful. Beautiful people herd together. And get together.") but Allison loudly orders some of the lacrosse guys to move down the bench. It leaves more than enough room for one person to sit, and soon enough Lydia and Scott are sliding in next to Allison.

The girl gives him a tight smile, and Stiles realises he has been staring.

The general conversation soon turns to the night's plans. Stiles had just declined Danny's invite to check out some newly opened club a short drive out of Beacon Hills (clubs aren't really his thing, he's more of a stay at home and marathon Star Wars kind of guy) when Allison starts snapping her fingers in front of his face. "Sorry - what did you say?"

"I said, do you want to come bowling with Scott and Lydia?"

He agrees before the 'with Scott and Lydia' part registers. And Allison looks so excited he doesn't have the heart to backtrack. So instead he puts on his best cocky face and tells them to "Prepare to get your butts kicked by Stilinski and Argent."

("You look terrible when you try to be cocky." Allison tells him later.)

Turns out, they get their butts kicked by Lydia and Scott instead. Or rather, by Lydia, single-handedly. Stiles and Allison are fair bowlers, but even together they cannot match up to Lydia's perfect form (seriously, what can't Lydia Martin do perfectly?). Her series of strikes easily carries Scott, who considers himself to be in good form tonight since he gets less gutterballs than usual.

"New personal best," the tan boy grins, plopping down next to Lydia after ending the round with a six. The girl laughs and slings her arm around his shoulders. "Don't worry, I got you covered."

They decide to take a break and Allison and Scott go to get more chips and Stiles has to remind her that if they can't finish the mega box, they'll have to bring it home, and then their dad will eat it, which will be bad for his health. When he turns back, Lydia is staring at him with an odd expression.

"Sorry," she mumbles, looking down. A light blush covers her cheeks, and Stiles resists the urge to tell her how adorable she looks.

Then she looks up at him again with those jade irises and he is so stunned by the catchlights in them he nearly doesn't hear what she is saying.

"I, uh...When you told Allison you had to bring home the chips, you made it sound like, um...I was wondering...you also said 'dad' as if..."

"Oh," he says. She's not the first person to be confused by the way he and Allison act around each other. "We're siblings. Our families were close so we knew each other since we were young. Her parents were in a hunting accident and she doesn't have any close relatives so my dad took her in," he explains.

Lydia is a little shocked, unsurprisingly. But she recovers quickly and nods, a small smile on her lips. "That's really nice of you and your dad."

"Well, we were already like siblings, just that now it's official," Stiles replies. "My childhood memories are her bossing me around while playing games."

A giggle escapes her lips and she immediately presses the back of her hand over her mouth, but he can still see the grin on her face and wow, he just made Lydia Martin smile and laugh. He must be on a roll tonight.

Their friends return with more snacks and Lydia gleefully turns to Allison.

"Will you be coming to the first game next week?" she asks, taking her drink.

"Of course," Allison replies as she hands everyone their orders. "I need to see if my brother is actually as good as lacrosse as he claims."

Of all the reactions to the sibling news, Scott's gaping mouth is by far the most hilarious.

* * *

Game day quickly arrives and before they know it, Coach is making sports analogies during lessons - his start-of-season tradition. It doesn't help that Economics is the last class of the day on Tuesdays.

Preparation starts as soon as class ends so Stiles doesn't see Allison or Lydia until the evening, when everyone is slowly pouring into the bleachers. He spots a patch of strawberry blonde amongst the sea of heads and quickly makes his way over. He finds the two girls together, chatting with Scott.

"Hey!" Allison calls when she sees him. She pulls him into a one-armed hug as soon as he is within arm's reach of her. "Good luck and have fun," she says excitedly into his shoulder. Stiles brings one hand up to rub her back. "Aww, thanks Al. Hey Lydia," he says when they break apart.

Lydia smiles. "Good luck, Stiles," she tells him softly.

"MCCALL! STILINSKI! QUIT TALKING TO YOUR GIRLFRIENDS AND GET YOUR ASSES OVER HERE!"

Both boys groan and Allison pretends to blow him a kiss. "All the best!" she yells as they jog back to the team.

* * *

The game is going well - good enough for an uprising team that has a record of losing its first few matches before making a comeback later in the season (they made it to the championships last year despite an early losing streak, thank you very much). Yes, they were losing but they weren't that far behind.

The game starts to turn at half time when Coach finally lets Scott on the field (he's not allowed to play full games because of his asthma). Scott might suck at bowling, but he has been working on lacrosse and it pays off. His field position is next to Stiles' and they guard each other whenever either gets the ball. Not that it happens very often because Jackson is a flamboyant one-man show. But then the opposing team starts getting rougher and Jackson gets tackled more often (ha, serves him right), leaving Scott to pick up the ball.

Scott starts scoring - and becomes the next target. Two big guys ram into him and he goes sprawling, ankle twisted. Coach subs in a defensive player and they change formation, leaving Stiles alone in the midfield. There is a scuffle towards the opponent's side of the field and suddenly the lone lacrosse ball is ejected from the pile of students, arcing through the air and finally landing at Stiles feet.

Stiles stares at the ball an back at the now-confused pile of players when it suddenly occurs to him that the game is still on and he hastily scoops up the ball and darts off towards the Cyclone's goal. The roaring crowd gives him away and he makes the mistake of looking back to see a hoard of blue-clad players hot on his tail. He lets out an embarrassing screech and picks up his pace, ducking past a defender.

He doesn't know why, but he grinds to a halt a few feet away from goal and suddenly his mind goes blank. He knows if he scores the game will be tied and overtime will start, but what if he doesn't? The air suddenly gets heavy and he frantically glances around, jumping when he sees the blue players closing in on him.

And then he spots her in the crowd, her creamy sweater complimenting her strawberry blonde hair. She's grabbing onto Allison's arm painfully and it's as if he hears her screaming at him all the way from the bleachers. "SHOOT IT!"

His body jerks into action and he shoots. Someone crashes into him from the side and the next thing he registers is Danny Mahealani yelling into his ear.

"Way to go Stilinski!"

"We're tied!"

Stiles looks up. Behind the stands the secondary scoreboard flashes the two equal numbers but his eyes quickly glance over, instead searching the crowds. He sees Allison jumping up and down with her hands in the air and his heart swells when he sees the proud look on her face. Then his eyes land on the shorter girl next to her, smiling and clapping. At him. For him. It's enough to help him extend his scoring record and carry the team to victory.

* * *

Allison pounces on him the moment he detangles himself from his congratulating teammates, screaming in his ear (so many people have been doing that tonight Stiles is surprised he hasn't gone deaf). "You were amazing!" she yells as he stumbles from the impact. Then she has grabbed him hand and is dragging him over to the bench.

Lydia grins widely when she sees him and throws her arms around his neck. "Stiles!" she exclaims. "Wow, that was great."

"Thanks," he manages, overwhelmed by the peachy scent of her shampoo, and the feeling of her arms behind his neck, or her body pressed up to his. Then she suddenly steps back and ducks her head, but remains smiling up at him shyly through her eyelashes and he realises he just got _hugged_ by Lydia Martin. There's probably a dopey look on his face.

Scott's ankle is wrapped up and he also has a few cuts on his face, but he is also smiling broadly, making him look like an excited puppy. "Good job, man," he says as Stiles collapses onto the bench next to him.

"You too. Not a bad start this year, huh?"

* * *

The post-game hype lasts exactly a week, and come the next Wednesday has been replaced with excitement and anticipation for the Winter Formal.

Stiles and Allison walk into a hallway full of chatter and pale blue posters, one of which has been stuck in front of his locker. It detaches itself and floats to the floor when he pulls the door open and is quickly swept up by another student.

He hears a familiar squeal coming from down the row and shuts his locker to see balloons and streamers coming out of his sister's. Allison bats the balloons out of her face and retrieves a colourful card. Stiles doesn't have to read it to guess it contents.

He is intrigued, however, when Allison spins around and throws her arms around none other than Scott McCall. He looks around and doesn't find Lydia and he frowns because the four of them have been hanging out more since the lacrosse game and he does not recall any signs of anything happening between the usually inseparable pair. But then the bell rings and he winds up in Chemistry with a challenging pop quiz that gets his mind off this new turn of events for the rest of the day.

* * *

School ends early because the teachers have a staff conference, and Allison decides this is the perfect opportunity to go dress-shopping. She ignores his complains as she turns onto the road heading downtown instead of towards their house and Stiles silently wishes it was his turn to drive them to school today.

"Oh quit sulking," Allison huffs as she drags him into the second department store. "You need to get a suit too."

"No I don't," he retorts. "I'm not going." He will be staying at home with a large bowl of chips and the Force to keep him company.

"Yes you are, because I took the liberty of finding your sorry ass a date."

"I'm sorry, what?" He stares at his sister, who is innocently texting someone on her phone. Stiles pushes her hands down, forcing her to look at him. Allison shrugs as if her setting him up is no big deal. "You don't have the balls to ask anyone yourself so I asked on your behalf."

"Oh really," he replies dryly. "And who has the honour of being my ass's date to the formal?"

Allison looks at him with a mischievious glint in her eye. The she turns to face the women's shoes section. "Her."

Stiles follows her line of sight, and his heart stops, because right there, stumbling as she tries on a pair of high heels, is the one and only Lydia Martin. Lydia regains her balance and looks up, spotting him. Her face turns red. Probably not as red as his.

* * *

The weather changes slightly (welcome to California) and Stiles finds himself killing the engine in the school parking lot with trembling hands - not an easy feet. Next to him, Lydia is still shrugging off the oversized fleece jacket she had on when he picked her up earlier (it was slightly chilly that night and her dress was strapless after all), so he takes this opportunity to rush to the other side of the jeep. He pulls the door open with a little flourish of his free hand (which, in his opinion, was more jerky than graceful). Lydia hops out of the passenger seat and her hand immediately shoots out to grab his arm when she stumbles in her heels. He somehow ends up with a hand on her waist which he quickly retracts once she's regained her balance. He takes a large step back as an extra precaution, and for the first time that night he gets to take her all in at once.

Sure, he'd seen the dress after Allison forced him to help Lydia carry dresses for trying around the store that day, but he had not yet seen her _in_ it, without any jackets blocking parts of the view. Her hair is pinned back and the light make-up she has put on make her eyes look wider and brighter than usual, matching the metallic sheen of the dress material.

Her head tilts. "What?"

He tries to reply, only to find his mouth already, and oh crap, she just caught him staring. Gaping. He swallows. "I just think you look beautiful."

It's already quite dark outside, so he can't see her blushing as she replies. "Really?"

He doesn't quite know how to respond to that, so he offers her his arm instead, nearly ripping his dad's suit in his excitement. She pulls her lips in slightly, gives him a small, shy smile, and links her arms with his.

A funky song is playing when they walk into the crowded school gym. Stiles scans the mass of moving bodies until he finds Allison, eyes crinkled with laughter as she videos Scott doing some weird dance moves with Danny. The little show is broken up with an exasperated "Dammit McCall!" when Coach pushes past and nearly gets slapped by Scott's flailing arms. Allison stops her recording and looks up. Her eyes narrow to slits when her eyes meet Stiles'.

"Took you long enough," she yells over the music. "I thought you would reach before me."

She's not wrong, he would have if he had not paced up and down the Martins' front porch for fifteen minutes before he finally racked up the nerve to ring the doorbell.

Scott comes over and tells them which punch bowls have not been spiked, then the music changes and Allison is pulling him into the sea of dressed-up students to dance. Lydia and Stiles stand around for a few awkward moments before he finally asks if she wants to get a drink while they're still alcohol-free, and they make their way to the sides of the gym without speaking.

A row of makeshift bleachers are open and they make themselves comfortable, sipping their punch in silence. Lydia has not said a word since she greeted Allison and Scott, the couple she is watching dance across the room. Occasionally her eyes flicker over to him, and she'll sigh and turn back to the dancing couple. Stiles suddenly remembers the oddity of Scott and Lydia not coming to this formal together. He wonders if Lydia wanted to come with Scott, if she was here now only because she didn't want to turn down Allison when she set her up. Then again, he too would not be here if his sister had not gotten him a date. He needed his sister to ask the girl out for him. Five years later he would probably look back on this night and judge himself for having zero guts.

But right now? He was going to make this night memorable for Lydia. Even if it was not the date and dance she had been looking for, he wanted her to at least have some fun. She took his breath away when she gave him that small smile earlier tonight; he wanted to leave this dance not breathing.

Stiles pushes himself onto his feet and faces his date. "Wanna dance?"

Lydia's body tenses and she looks down. Her brow furrows as she thinks before she looks up and answers him. "Do you want to?"

 _Absolutely_. "Yeah," he says offhandedly, then stumbles to clarify himself. "I mean, if you want to dance, that is."

"You want to dance with _me_?" is her next question, and Stiles pinpoints the odd expression on her face - confusion, and disbelief?

He pushes his hair back (a newly developing nervous tic, he notices) and Lydia's eyes following the action unblinkingly. Which makes him even more nervous because now she knows he's nervous. He's probably degrading himself in her eyes right now, and pretends to rub the back of his neck to hide his clenched fists (which doesn't help his nervousness at all) (It doesn't occur to him that she's staring at the tensed up muscles in his arm.)

A few moments pass, and Lydia takes his speechlessness as a reconsideration. Her arms flops onto the small table next to them, the empty cup it was holding falls over. "You don't have to give me a pity date," she tells him quietly.

 _Oh_. So that is what she thinks this is. Sure, whatever made her upset enough not to attend school that day (Lydia loves learning, she would never skip for nothing), he's sorry. She deserves better. But -

"You are _not_ a pity date," he breathes. Lydia continues to look away, so he fills the silence with an explanation. "I'm sorry about Scott, I don't know what happened between you guys, but that day at the mall, you seemed a little down, so I figured you guys...I just thought dancing would help cheer you up. It's okay if you don't want to dance with me. Or at all, for that matter..." he rambles.

"I was upset because I got a B-plus in Math," Lydia interjects quietly.

"So you didn't break up with Scott?" The questions tumbles past his lips before he gets to reign in his curiosity.

Lydia's head snaps up on 'break up' and he fixes him with those wide doe eyes. They're shining with understanding, but he mistakes them for forming tears and his heart pounds. Great, now you made her cry. That was such an insensitive remark, good job self.

"Scott is great, but he is just my best friend."

Okay, he's pretty sure his heart just stopped.

But Lydia seems determined to put him in metaphorical cardiac arrest. "I mean, we kinda agreed to come together as friends but at that time we didn't have anyone but each other, and he has Allison now, who is really nice by the way, and I just thought she felt bad for spoiling our plans so she set me up with you, and you didn't say no because you felt bad for me too," she mumbles.

"Oh god no - " he makes to correct her. "I mean, I would feel bad if your plans got ruined, but it could have been every other girl in school and I wouldn't have given in to Allison so easily. And if I had known you and - no, I might still need Allison to ask you out for me, but what I'm trying to say is, I wanted to come with you anyway."

And then everything he had ever felt for her broke through the dam in his heart. "Lydia, I've been in love with you since the third grade. You're really smart, but you are also compassionate, the way you always look out for Scott and make sure he takes care of his health. You're so amazing that one day you're gonna get out of this town and write some insane mathematical theorem that wins the Nobel prize, okay? And I wanted - I _want_ to be here with you right now, because, Lydia, you are so much more than a pity date."

He didn't realise he had made that whole speech until he found himself panting. Lydia's gaze dropped back to her feet. The pink strobe lights have nothing on the red colour creeping up her cheeks and he suddenly recalls her blush when he complimented her. She was an incredibly beautiful person inside and out, who didn't see it for herself, and all this time, she was right in front of him.

Finally, _finally_ , Lydia stands up and takes a step towards him. "Fields' Medal," she says. Her eyes travel up the length of his body and - _did she just check him out?_

"The Nobel doesn't have a prize for math," she explains. "Fields' Medal is the one I'll be winning." Then she reaches out and takes his hand in hers, angling her body towards the dance floor. "So, shall we?"

* * *

They party dance, twisting and shaking to the latest hits. They slow dance, hands clasped together, hanging by their sides and they turn lazy circles on the floor. They take a break and get more drinks and chat with their friends before their back in the dancing crowd, and Lydia laughs - eyes closed to slits, mouth wide open, head thrown back laughs - when he tries to tango to a techno song. It's the most magical sound Stiles has heard.

They soon find themselves slow dancing again, closer this time, bodies gently leaning against each other. Her hands are on his shoulders and his on her waist, holding each other close. Her head is buried in the crook of his neck. Her peachy scent and the tune of the song playing will forever be imprinted in his memory.

He feels Lydia shift and opens his eyes to find her green ones staring at him. They've stopped turning but are still swaying to the music. They gaze at each other, until he breaks the silence.

"What is it?" He doesn't know why he's whispering, but it feels like they are having a moment and he doesn't want to break it by being too loud.

Lydia smiles and shakes her head. "It's just hard to believe," she replies in an equally soft voice.

"What is?"

"You," she answers without breaking eye contact. "What you said earlier, I always dreamed, but I never thought..." She trails off and turns away, but Stiles brings his hand to her cheek, tilting her head back up. Brown eyes seek green as he implores he to say what she was going to say.

She takes a deep breath. "Everything you said...I feel the same way. You're kind and funny and you're also pretty smart yourself, but you're also good-looking and well-liked, I thought only in my dreams you would notice someone like me."

His heart soars. It takes every ounce of his self-control not to burst into a victory dance. (His victory dances are _not_ pretty. Also it would ruin this tender moment.) So he wraps his arms around her waist, bringing them impossibly closer.

"I hope you've found a different meaning of 'someone like you'," he mumbles into her ear.

Her arms find their way around his neck and all the planes of their bodies intersect and overlap as they embrace tightly.

"I didn't have to," she whispers into his shoulder. "You found it for me."


End file.
